1. Field of the Invention
The present invention relates to a method and an apparatus for removing a magnetic head slider and, more specifically, to a method and an apparatus for removing a magnetic head slider from a suspension in a head gimbal assembly which is judged as being a defective product in an assembling process thereof.
2. Description of the Related Art
As high-speed, highly reliable, and low-cost recording devices, hard disk drives (HDD) are widely used for reading/writing digital data. With an HDD, reading/writing of data to/from a magnetic disk is carried out by using a thin film magnetic head. This magnetic head comprises a suspension and a magnetic head slider. This magnetic head slider comprises an electromagnetic conversion element which carries out reading/writing of data. The suspension holds the magnetic head slider through fixing it by adhesive or solder to a gimbal spring part of a flexure which constitutes the suspension.
When manufacturing the magnetic head, an inspection for checking a reading/writing property of the magnetic head can be performed only after the magnetic head slider and the suspension are assembled. Thus, defective products are found after the assembling. The defective rate thereof is extremely higher than the defective rate found in the suspension alone so that a strict inspection is required after the assembling. With this, it eliminates a risk of having the detected defective products remained in shipping products so as to improve the quality.
However, if the above-mentioned defective product as a whole is to be dumped, the suspension is also dumped along therewith even though, for example, there is only reading/writing malfunction generated in the electromagnetic conversion element of the magnetic head slider. Since the suspension is usually more costly than the slider, the cost for manufacturing the magnetic head becomes strikingly increased. On the other hand, in the case where the magnetic head slider can be reutilized even though the suspension is defective, there causes a waste of parts as in the above-described case. Thus, the manufacturing cost is increased.
Therefore, in order to achieve a reduction in the manufacturing cost of the magnetic head, it is desired to carry out an inspection for checking the reading/writing property after assembling the suspension and the slider once, then, if there is a defective product found, the suspension and the magnetic head slider are separated so as to reutilize the fine magnetic head slider or suspension.
For satisfying the demand as described above, Japanese Patent Unexamined Publication No. 2002-150734 discloses a technique for removing a magnetic head slider from a suspension. The technique disclosed in JP-A 2002-150734 is to remove an assembled magnetic head slider, which is joined by an adhesive resin to a flexure that constitutes a suspension, by controlling a cure state of the adhesive resin through temperatures.
In the meantime, in a head gimbal assembly, solder is used for connecting a connection pad of the magnetic head slider and a lead trace formed on the flexure. Also, there may be cases where the magnetic head slider is fixed to the flexure as the suspension by solder. In that case, it is not possible to deal with the solder fixation by using the technique for removing the magnetic head slider, which is disclosed in JP-A 2002-150734. In the case where, as described above, the magnetic head slider is removed form the flexure in the head gimbal assembly in which parts are joined by the solder, it is necessary to melt the solder by applying heat. As described above, conventionally, a method which is to heat the entire magnetic head up to a melting point of the solder has been employed.
However, with the above-described method, the temperature of the entire magnetic head may be increased as high as the melting pint of the solder or more thus damaging the electromagnetic conversion element of the magnetic head slider. That is, there is a risk of breaking the electromagnetic conversion element since the general melting point of the solder is at about 230° C., while the critical temperature of a reading element (MR element) is at about 250° C. When that happens, it cannot be reutilized even though there is no defect in the suspension, which results in wasting the parts. Further, the suspension is also heated entirely so that the rigidity of the suspension may be affected by the heat.
Furthermore, the above-described method simply removes the magnetic head slider by melting the solder. Thus, there may be the solder remained attached to the magnetic head slider or the suspension. In that case, before reutilizing the magnetic head slider or the suspension, it is necessary to carry out processing for removing the attached solder. Therefore, there may cause a problem that manufacturing procedures are increased and the time and cost thereof are increased as well.